1. Field of the Invention
The present invention relates to an electric device testing apparatus for testing an electric device, such as a semiconductor integrated circuit element (hereinafter, referred to representatively as an IC chip), and the method, more specifically relates to an electric device testing apparatus which can perform a test at a correct temperature considering heating of the electric device itself during the test and the method.
2. Description of the Related Art
A testing apparatus for testing a finally produced device, such as an IC chip, is necessary in a producing process of a semiconductor device, etc. As one kind of such testing apparatuses, an apparatus for testing an IC chip under applying a thermal stress of a normal temperature, a higher temperature and a lower temperature than a normal temperature is known. It is because IC chips are required to guarantee as a feature thereof to operate well under a normal, high and low temperature.
A test is carried out in such an electric device testing apparatus, wherein an upper portion of its test head is covered with a chamber for providing a sealed space, an IC chip is conveyed to above the test head under a constant temperature environment of a normal, high or low temperature, where the IC chip is pushed against the test head for electric connection. The IC chips are preferably tested by the above test and sorted into at least good ones and defective ones.
Along with the recent IC chips becoming higher speed and more highly integrated, however, there is a tendency that the heat generation by itself during operating has become higher and heat generated by itself tends to become higher also during the IC chip testing. For example, some generates about as much as 30 watts of heat by itself depending on kinds of the IC chips.
Accordingly, when a high temperature test of about 125xc2x0 C. is carried out, for example, the quantity of heat by the self-heating in addition to that of the set temperature is applied to the IC chip, as a result, there arises a possibility that the temperature on the IC chip exceeds its tolerable limit. Also in a normal or low temperature test, even if inside the chamber is made to be at a constant temperature, it becomes difficult to carry out a test under a desired testing temperature due to a quantity of heat generated by the self-heating of the IC chip.
Although it has been studied to provide a sensor for detecting a temperature of the IC chip close to the IC chip and to feed back the actual temperature of the IC chip detected by the sensor to a temperature applying device, there is a limit to provide the temperature sensor closer to the IC chip and the heat resistence between the IC chip and the temperature sensor cannot be made to be zero. Therefore, the true temperature of the IC chip cannot be detected as long as using an externally provided sensor.
An object of the present invention is to provide an electric device testing apparatus which can carry out a test under a correct temperature by considering self-heating of the electric device during the test and the method.
(1) To attain the above object, according to a first aspect of the present invention, there is provided an electric device testing apparatus for carrying out a test by pushing a terminal of an electric device to be tested against a contact portion of a test head, comprising a temperature calculation means for calculating an actual temperature of the electric device to be tested based on a signal from a temperature sensing element provided to the electric device to be tested.
Also, according to the first aspect of the present invention, there is provided an electric device testing method for carrying out a test by pushing a terminal of an electric device to be tested against a contact portion of a test head, including the steps of detecting an actual temperature of the electric device to be tested based on a signal from a temperature sensing element installed in the electric device to be tested; and performing feed-back control at the detected temperature.
In the electric device testing apparatus and the method according to the first aspect, since an actual temperature is calculated based on a signal from a temperature sensing element provided on an electric device to be tested, a true temperature of the electric device to be tested can be detected without being affected by noise of heat resistence, etc. as a result, a test can be carried out at a correct temperature to be aimed and the reliability of the test results improves.
As a temperature sensing element according to the present invention is not specifically limited, however, when using diode having rectifying characteristics, the relationship of an output value with respect to the temperature becomes interrelated so the actual temperature can be easily calculated. Such a temperature sensing element can be produced exclusively for an electric device to be tested, but when applying an element produced as an electric device, it is possible to prevent increase of the costs for producing the electric device.
The actual temperature of an electric device to be tested calculated by a temperature calculation means is sent to an applying temperature control means for controlling a temperature to be applied to the electric device to be tested, a temperature applying means is controlled by a control signal from the applying temperature control means, and the temperature to be applied to the electric device to be tested is set to be an appropriate value.
In the above invention, places of the temperature calculation means and the applying temperature control means are not specifically limited, and they can be provided on a handler for handling the electric device to be tested and on a tester for sending a test signal to a contact portion to carry out a test of the electric devices to be tested. Also, the temperature calculation means and the applying temperature control means can be configured as separate devices.
(2) To attain the above object, according to the second aspect of the present invention, there is provided an electric device testing apparatus for carrying out a test by pushing a terminal of an electric device to be tested against a contact portion of a test head, comprising a temperature storing means for storing data about an actual temperature of the electric device to be tested under the test conditions obtained in advance; and an applying temperature sending means for sending data relating to the actual temperature of the electric device to be tested stored in the temperature storing means at the time of sending the test signal.
Further, according to the second aspect, there is provided an electric device testing method for carrying out a test by pushing a terminal of an electric device to be tested against the contact portion of the test head, including the steps of obtaining in advance data relating to an actual temperature of the electric device to be tested under the test conditions; and performing feed-forward control by the data relating to the actual temperature.
In the electric device testing apparatus and the method according to the second aspect, data relating to an actual temperature of an electric device to be tested under respective test conditions is obtained in advance and is sent in accordance with a test flow. Therefore, when obtaining a true temperature of the electric device to be tested or data relating to that without noise, such as heat resistance, a test can be carried out at an aimed correct temperature and the reliability of the test results improves.
Additionally, according to the present invention, since a so called feed-forward control becomes possible, when a desired temperature is sent in advance, it is possible to shorten the time to reach the desired temperature after conveying the electric device to be tested.
Note that the data relating to the actual temperature of the electric device to be tested from an applying temperature sending means is sent to the applying temperature control means, the temperature applying means is controlled by a control signal from the applying temperature control means, and the temperature to be applied to the electric device to be tested is set to an appropriate value.
The above data relating to the actual temperature in the invention includes a temperature control pattern, etc. in addition to data of an actual temperature.
In the above invention, places of the temperature storing means and the applying temperature sending means to be provided are not specifically limited, and they can be provided on a handler for handling an electric device to be tested, and on a tester for sending a test signal to a contact portion to carry out a test of the electric device to be tested. Also, the temperature storing means and the applying temperature sending means can be configured as separate devices.
Especially, when providing the temperature storing means and the applying temperature sending means on the tester, it is preferable to be integrated in an operation instruction program from the tester to the handler for handling the electric device to be tested. By doing so, operation instruction processing becomes remarkably easy and correct, further, it can be made only by changing or adding to the software without newly providing, changing or modifying a hardware.
(3) In the above invention, the specific configuration is not specifically limited as to the temperature applying means for applying a temperature to make an electric device to be tested become a predetermined temperature, and it may be any configurations. Also, the temperature to be applied includes all temperatures of high, normal and low.
An electric device to be tested applied in the present invention is not specifically limited and all kinds of electric devices are included, but the efficiency becomes especially remarkable when applying an IC having a large quantity of self-heating during operation.